Go into the camera and check there. From the looks of the interface I can see straight away you're only checking in the NVR. The cameras use the new interface and it's blue and more pictorial. There could be rules set in the camera interface that are generating triggers detected by the NVR over ONIV.
Also, make sure you log into the 4kx /t's using IE. With other browsers, the settings will often revert. It happens as well with IE just not as much. The 4KX / T's are still a little temperamental on remembering settings.
My best guess is either motion detection (most likely) or trip wire rules are set up in the camera and it's sending an ONIV signal to the NVR which is then responding by recording. If you want to use NVR generated rules to detect, you need to make sure all in camera triggers are turned off, otherwise you're just duplicating alerts.
BTW As an aside, I like the new interface once you get used to it. The pain is the fact the camera has a habit of forgetting / reverting the settings itself occasionally.